1. Field of the Invention
This invention relates to the oral dosage forms of lectins and the medicinal use of these preparations, especially of Abrin and Abrus agglutinin for the suppression of post-surgical malignant tumor metastasis. This invention also relates to a method of treatment comprising the daily oral administration of Abrin and Abrus agglutinin post-surgically, in conjunction with and/or subsequent to, radiation therapy and/or chemotherapy to suppress malignant tumor metastasis.
This invention further relates to oral dosage compositions of Abrin and Abrus agglutinin with no other active agent, or in combination with a cancer chemotherapy agent for a post-surgical lectin treatment in conjunction with chemotherapy.
Traditionally, lectins have been administered to cancer patients parenterally, a treatment that had to be performed by physicians in a hospital. The clinical use of lectins has been hindered by this requirement that lectin compositions be administered to a cancer patient in a hospital under direct physician supervision. There is also an element of risk involved with the parenteral administration of a drug.
There exists, therefore, a great need for safer, orally-administerable lectin compositions that a cancer patient can self-administer without direct physician supervision, to expand the clinical use of these compositions. As described in greater detail hereinafter, the compositions of this invention comprise lectins in an orally-administerable form demonstrating significant anti-cancer effects, especially in the inhibition of metastasis.
2. Objects of the Invention
The invention provides orally administerable anti-metastaic lectin compositions and methods of treatment, which have numerous practical applications for the suppression of malignant tumor metastasis. The invention provides a valuable contribution to the post-surgical treatment of cancer. The invention provides a safe, oral composition, easy to administer to a cancer patient without direct physician intervention. The invention provides a method of treatment for the post-surgical suppression of malignant tumor metastasis by the daily oral administration of lectin compositions in conjunction with and/or subsequent to chemotherapy and/or radiation treatment. The invention provides lectin compositions with no other active agent, or in combination with a cancer chemotherapy agent for a post-surgical lectin treatment in conjunction with chemotherapy.
Thus, an important object of the invention is to provide safe, orally-administerable lectin compositions which are effective in the suppression of malignant tumor metastasis and may be taken by a cancer patient without direct physician supervision.
Another object of the invention is to provide a post-surgical method for daily administering oral lectin compositions to a cancer patient in amounts effective to suppress malignant tumor metastasis. It is a further object of the invention to provide a method of treating a cancer patient with lectins to suppress malignant tumor metastasis in conjunction with and/or subsequent to radiation therapy and/or chemotherapy.
It is also an object of the invention to provide oral compositions wherein a lectin is the sole active ingredient as well as compositions wherein a lectin is combined with a cancer chemotherapy agent for lectin therapy in conjunction with chemotherapy.
The listing of objectives provided herein, or of features of the invention, is not intended to be exhaustive, but merely illustrative.
Other objects will become apparent to one of average skill in the art in the further description of the invention.
3. Brief Description of the Prior Art
Lectins are cell agglutinating proteins having specific affinity for a wide variety of carbohydrates. Many plants, e.g., beans, vegetables and medicinal herbs, contain various lectins in their seeds, leaves and bark, etc. (1). Phyto-hemaglutinin (PHA), Concanavalin-A (Con-A), Abrin, Abrus agglutinin (AAG), Ricin, Ricinus agglutinin, soybean agglutinin and wheat germ agglutinin are among the well-known lectins being isolated from plants. These glycophilic proteins have a specific affinity for carbohydrates and bind to the terminal monosaccharide moiety of cell membrane receptors (2). Consequently, capping occurs (3) followed by endocytosis.
Lectins enter into the cytoplasm, and elicit biological responses, for example; 1) induction of lymphokines such as interferons (4,5), 2) stimulation of DNA synthesis followed by mitogenic cell division (6), and 3) after entering the cells, suppression of protein and DNA synthesis (7). Lectins have been suggested to inhibit tumor or cancer cell development in vitro either directly, by mediation of macrophages or by activation of T lymphocytes (8-10). In vivo anti tumor effects of lectins has been demonstrated in animals after parenteral administration (11-13), but the use of orally administered lectins has not been reported in the literature. It has been further shown that a portion of the orally administered lectins bind to membrane receptors of lymphocytes on the gastro-intestinal walls and entered the body. Therefore, lectins in food, which have not been destroyed during cooking or digestion, are absorbed via the lymphatic system of the digestive tract, and exert their specific biological functions. It has also been demonstrated that Abrus agglutinin (AAG) and Abrin, isolated from seeds of Abrus precatorius induce r-interferons and consequently increase immunities against cancer (5).
Other prior art references considered in the preparation of this application include Lin, 1969 (15); Post, 1980 (16); Wang, 1982 (17) and Sharon and Lis, 1975 (18).